Question

我想知道有没有办法做自动循环/计数器批处理，像使用OFFSET / FETCH NEXT方法更新SQL列

问题：下表有20行，我喜欢将DealerId列的前4行更新为1,2,3,4，接下来的4行重复为1,2,3,4值

如下所示需要修改表

    Id  DealerId
1   1   1
2   2   2
3   3   3
4   4   4
5   5   1
6   6   2
7   7   3
8   8   4
9   9   1
10  10  2
11  11  3
12  12  4
13  13  1
14  14  2
15  15  3
16  16  4
17  17  1
18  18  2
19  19  3
20  20  4

ORIGINAL TABLE

Id  DealerId    StoreId TerminalId  MessageNo   CreatedDate
1   1   86  5027    029500021201403031434350039 2014-03-03 14:34:37.347
2   2   86  5027    029500021201403031434350039 2014-03-05 10:31:59.903
3   3   86  5027    029500021201403031434350039 2014-03-05 10:33:41.293
4   4   86  5027    029500021201403031434350039 2014-03-05 10:46:50.057
5   5   86  5027    029500021201403031434350039 2014-03-05 10:50:23.910
6   6   33  5338    004000003201403051508010255 2014-03-05 15:08:03.247
7   7   26  5595    704201181201403061024330013 2014-03-06 10:24:34.590
8   8   26  5595    704201181201403061026180022 2014-03-06 10:26:19.517
9   9   33  5338    004000003201403061043150312 2014-03-06 10:43:16.013
10  10  86  5027    029500021201403031434350039 2014-03-06 14:27:51.717
11  11  86  5027    029500021201403031434350039 2014-03-06 14:38:40.593
12  12  86  5027    029500021201403031434350039 2014-03-06 14:44:25.947
13  13  521 4905    051100003002447 2014-03-07 12:51:07.487
14  14  521 4905    051100003002447 2014-03-07 12:55:07.300
15  15  521 4905    051100003002447 2014-03-07 12:56:24.793
16  16  521 4905    051100003002447 2014-03-07 12:57:43.123
17  17  521 4905    051100003002447 2014-03-07 14:15:11.093
18  18  632 5120    088800003201403071441280026 2014-03-07 14:41:29.733
19  19  632 5120    088800003201403071456500050 2014-03-07 14:56:51.727
20  20  632 5120    088800003201403071459240064 2014-03-07 14:59:24.953

Answer 1

假设所有id都是，从1开始：

在MySQL中：

update OriginalTable
    set DealreId = mod(id-1, 4)+1

并在Microsoft SQL Server中：

update OriginalTable
    set DealreId = ((id-1)%4)+1

Answer 2

如果id不是（或者不是从1开始），你可以使用游标逐个更新它：

DECLARE c1 CURSOR FOR 
    SELECT id, dealerId
        FROM OriginalTable
        ORDER BY id, dealerId

OPEN c1

declare @id int
declare @dealerId int
declare @i int

set @i = 1

FETCH NEXT FROM c1
    INTO @id, @dealerId

while @@FETCH_STATUS = 0
    BEGIN

    update OriginalTable
        set dealerId = @i
        where current of c1

    if (@i < 4)
        set @i = @i + 1
    else
        set @i = 1

    FETCH NEXT FROM c1
        INTO @id, @dealerId

    END

SQL更新后续列OFFSET FETCH NEXT

2 个答案: